: Non-breeeding. mid Jun-mid Jul anywhere on saltwater but most frequently in the .
: Complex. late May-early June mostly through the but also where few data. late Jul-late Oct in the , where birds arrive early and molt before continuing their , with to late Dec. Probably Oct-early Nov but few data.
: on saltwater Dec-Feb. A bird in nearby Trenton Apr 23, 2026 was suspected of wintering locally.
There are no records at any season from freshwater.
Miscellany: Bonaparte's Gull is the only one of the world's gulls that usually nests in trees.
Last Reviewed: May 22nd, 2026